实体框架持久性问题给出“ObjectStateManager不包含ObjectStateEntry，引用类型为...的对象”

Question

在我拥有的数据库中：

PK CountryID int notnull
PK ServiceID int notnull
PK TaskID int notnull
PK TaskItemID int notnull
PK CorrespondentID int notnull
PK PreviousTask int notnull
   IsOnTimeline bit not null
   ..and 5 other nullable fields

我正在使用此复合键来确保“ServiceSchedule”项的唯一性。 “Previoustask”字段是所有PK的串联，这个想法是我可以建立一个从记录到记录相关的细化“ServiceSchedule”任务时间线。

背景是：

UPEntities db = new UPEntities(); for all workings here (i.e. repository and db).

两个Edit控制器操作如下所示：

     public ActionResult Edit(int countryid,
                                int serviceid,
                                int taskid,
                                int taskitemid,
                                int correspondentid)
    {
        var t = (from s in repository.GetServiceSchedules()
                            where s.CountryID == countryid
                            where s.ServiceID == serviceid
                            where s.TaskID == taskid
                            where s.TaskItemID == taskitemid
                            where s.CorrespondentID == correspondentid
                            select s).First();

        return View(t);
    }



    [HttpPost]
    public ActionResult Edit(ServiceSchedule serviceToEdit)
    {

        var originalService = (from s in repository.GetServiceSchedules()
                               where s.CountryID == serviceToEdit.CountryID
                               where s.ServiceID == serviceToEdit.ServiceID
                               where s.TaskID == serviceToEdit.TaskID
                               where s.TaskItemID == serviceToEdit.TaskItemID
                               where s.CorrespondentID == serviceToEdit.CorrespondentID
                               select s).First();


       if (!ModelState.IsValid)

         return View(originalService);

         db.ApplyPropertyChanges(originalService.EntityKey.EntitySetName, serviceToEdit);        //Code throws exception here.......
         db.SaveChanges();

         return RedirectToAction("Index");           
    }

似乎一切正常，直到“db.ApplyPropertyChanges”行，我得到错误：

The ObjectStateManager does not contain an ObjectStateEntry with a reference to an object of type 'ProjectName.Models.ServiceSchedule'.

我注意到传递到编辑视图的模型包含来自相关表的集合（例如，CountryID中的国家/地区集合）但是当模型从视图返回时它只包含来自“ServciceSchedule”表的PK ID没有相关的收藏品。

我目前正试图通过在视图中创建隐藏页面来解决这个问题，但仍然无法将完整的模型重新放回控制器：

<% using (Html.BeginForm())
   {%>
    <%= Html.ValidationSummary(true)%>

    <fieldset>
        <legend>Fields</legend>


        <div class="editor-label">
            <%= Html.HiddenFor(model => model.CountryID)%>
        </div>

        <div class="editor-label">
            <%= Html.HiddenFor(model => model.ServiceID)%>
        </div>

        <div class="editor-label">
            <%= Html.HiddenFor(model => model.TaskID)%>
        </div>

        <div class="editor-label">
            <%= Html.HiddenFor(model => model.TaskItemID)%>
        </div>

        <div class="editor-label">
            <%= Html.HiddenFor(model => model.CorrespondentID)%>
        </div>



         <div class="editor-label">
            <%= Html.HiddenFor(model => model.Services)%>
        </div>

        <div class="editor-label">
            <%= Html.HiddenFor(model => model.Tasks)%>
        </div>

        <div class="editor-label">
            <%= Html.HiddenFor(model => model.TaskItems)%>
        </div>

        <div class="editor-label">
            <%= Html.HiddenFor(model => model.Correspondents)%>
        </div>


        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.PreviousTask)%>
            <%= Html.ValidationMessageFor(model => model.PreviousTask)%>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.Cost)%>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.Cost, String.Format("{0:F}", Model.Cost))%>
            <%= Html.ValidationMessageFor(model => model.Cost)%>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.ChargeOut)%>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.ChargeOut, String.Format("{0:F}", Model.ChargeOut))%>
            <%= Html.ValidationMessageFor(model => model.ChargeOut)%>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.DurationInDays)%>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.DurationInDays, String.Format("{0:F}", Model.DurationInDays))%>
            <%= Html.ValidationMessageFor(model => model.DurationInDays)%>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.JobSection)%>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.JobSection)%>
            <%= Html.ValidationMessageFor(model => model.JobSection)%>
        </div>

        <div class="editor-label">
            <%= Html.LabelFor(model => model.JobSectionGroup)%>
        </div>
        <div class="editor-field">
            <%= Html.TextBoxFor(model => model.JobSectionGroup)%>
            <%= Html.ValidationMessageFor(model => model.JobSectionGroup)%>
        </div>

        <p>
            <input type="submit" value="Save" />
        </p>
    </fieldset>

<% } %>

此外，GetServiceSchedules存储库如下所示：

public class ServicesRepository
{
    UPEntities db = new UPEntities();


    public List<ServiceSchedule> GetServiceSchedules()
    {
        return db.ServiceScheduleSet.Include("Countries")
                                    .Include("Services")
                                    .Include("Tasks")
                                    .Include("TaskItems")
                                    .Include("Correspondents")
                                    .ToList();
    }

}

（使用VS 2008，SQL 2008，MVC2）

任何人都可以让我知道一些更有针对性的补救措施吗？